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1.
Food Chem ; 307: 125554, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31648176

RESUMO

The reaction of Nε-(carboxymethyl) lysine (CML) with eight kinds of non-flavonoid o-benzoquinones and five kinds of flavonoid o-benzoquinones were investigated by cyclic voltammetry at pH 5.0, 7.0 and 8.0 and scan rate of 10, 50 and 100 mV/s. The reactivity of o-benzoquinones towards CML is weakened by the electron-donating substituent and strengthened by the electron-withdrawing substituent on the o-benzoquinone rings. The steric hindrance of the substituents on o-benzoquinone rings also weakens the quinone reactivity. Reaction of 4-methylbenzoquinone with CML (38.0 ±â€¯1.3%) was found to be faster than that with l-lysine (31.3 ±â€¯1.5%) and Nα-acetyl-l-lysine (14.5 ±â€¯0.1%) but slower than that with l-cysteine (≥100.0%) and Nα-acetyl-l-cysteine (≥100.0%) at pH 7.0 and scan rate of 10 mV/s. Products obtained by the reaction of CML with o-benzoquinones were found to include a CML-quinone adduct according to the cyclic voltammetry and UPLC-QTOF-MS/MS analysis.


Assuntos
Benzoquinonas/química , Lisina/análogos & derivados , Catecóis , Cisteína/química , Flavonoides , Lisina/química
2.
J Agric Food Chem ; 68(1): 340-350, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31874034

RESUMO

Folic acid, a synthetic form of folate, is a water-soluble vitamin that is essential during periods of rapid cell division and growth. However, it decomposes upon ultraviolet irradiation to form inactive photoproducts. In this study, the protective effect and mechanisms of antioxidants, including cinnamic acids, flavonoids, catechol and its derivatives, stilbenes, p-benzoquinone and its derivatives, isoprenoids, curcumin, oleic acid, and linoleic acid, against folic acid photodecomposition were investigated by using fluorescence and absorbance spectroscopy, high-performance liquid chromatography, and antioxidant assay. It was found that antioxidants could inhibit or delay the folic acid decomposition in varying degrees, among which caffeic acid was the most effective. The increase in its remarkable antioxidant efficiency and absorbance in the UVA region during irradiation contributed to its effective protection. This finding could be useful for the protection of photolabile components in food and other uses.


Assuntos
Antioxidantes/química , Ácido Fólico/química , Benzoquinonas/química , Catecóis/química , Cinamatos/química , Flavonoides/química , Fotólise/efeitos dos fármacos , Fotólise/efeitos da radiação , Estilbenos/química , Raios Ultravioleta
3.
Chemosphere ; 239: 124722, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494318

RESUMO

Perfluorooctanoic acid (PFOA) has attracted considerable attention worldwide due to its widespread occurrence and environmental impacts. This research focused on the photocatalytic process for the treatment of PFOA in water and wastewater. Gallium oxide (Ga2O3) and peroxymonosulfate (PMS) were mixed directly in PFOA solution, which was irradiated under different light sources. The treatment system showed excellent performance that 100% PFOA was degraded within 90 min and 60 min under 254 nm and 185 nm UV irradiation, respectively. Moreover, the degradation efficacy was unaffected by initial PFOA concentration from 50 ng L-1 to 50 mg L-1. Acidic solution (pH 3) improved the degradation process. The quantum yield in the PMS/Ga2O3 system under UV light (254 nm) was estimated to be 0.009 mol E-1. Scavengers such as tert-butanol (t-BuOH), disodium ethylenediaminetetraacetate (EDTA-Na2) and benzoquinone (BQ) were added into PFOA solution to prove that sulfate radicals (SO4•-), superoxide radical (O2•-) and photogenerated electrons (e-) were the main active species with strong redox ability for PFOA degradation in PMS/Ga2O3/UV system. Combined with the intermediates analysis, PFOA was degraded stepwise from long chain compound to shorter chain intermediates. In addition, PFOA in real wastewater exhibited similar degradation efficiency, together with 75-85% TOC removal by Ga2O3/PMS under 254 nm UV irradiation. Therefore, Ga2O3/PMS system was highly effective for PFOA photodegradation under UV irradiation, which has potential to be applied for the perfluoroalkyl substances (PFAS) treatment in water and wastewater.


Assuntos
Caprilatos/química , Fluorcarbonetos/química , Gálio/química , Peróxidos/química , Poluentes Químicos da Água/química , Benzoquinonas/química , Ácido Edético/química , Concentração de Íons de Hidrogênio , Oxirredução , Fotólise , Superóxidos/química , Raios Ultravioleta , Águas Residuárias/química , Água , Purificação da Água , Difração de Raios X
4.
BMC Complement Altern Med ; 19(1): 334, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31771651

RESUMO

BACKGROUND: Psoriasis, a recurrent, chronic inflammatory disorder of skin, is a common problem in middle age and elderly people. Thymoquinone (TQ), a lipid soluble benzoquinone is the major active ingredient of volatile oil of Nigella sativa (NS), possesses good anti-psoriatic activity. However, its hydrophobicity, poor aqueous solubility, and photosensitive nature obstructs its development. Therefore, in the present research work, ethosomal vesicles (EVs) loaded with TQ were assessed for its anti-psoriatic potential employing mouse-tail model. METHODS: TQ-loaded EVs were prepared by cold method, and characterized for various essential attributes, viz. particle size, morphology, percent drug entrapment, flexibility, rheological and textural analysis, and skin absorption. The optimized formulation was finally evaluated for anti-psoriatic activity on Swiss albino mice employing mouse-tail model for psoriasis. RESULTS: The spherical shaped vesicles were in the nanosize range, and had high flexibility. The EVs incorporated hydrogel was rheologically acceptable and resulted in substantial TQ retention in the skin layers. The % anti-psoriatic drug activity was observed to be substantially better in the case of TQ-loaded ethosomal gel vis-à-vis plain TQ, NS extract, and marketed formulation. CONCLUSIONS: The promising outcomes of the current studies ratify the superiority of TQ-loaded phospholipid-based vesicular systems for the management of psoriasis over other studied test formulations. This study, thus open promising avenues for topical application of TQ in the form of EV hydrogel.


Assuntos
Benzoquinonas , Portadores de Fármacos , Nanomedicina/métodos , Fosfolipídeos , Psoríase , Animais , Benzoquinonas/administração & dosagem , Benzoquinonas/química , Benzoquinonas/farmacocinética , Modelos Animais de Doenças , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Portadores de Fármacos/farmacologia , Camundongos , Nigella sativa/química , Fosfolipídeos/química , Fosfolipídeos/farmacocinética , Fosfolipídeos/farmacologia , Psoríase/metabolismo , Psoríase/patologia , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Absorção Cutânea/efeitos dos fármacos
5.
J Microbiol ; 57(11): 982-990, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31659684

RESUMO

Microalgae and bacteria are known to be closely associated in diverse environments. To isolate dominant bacterial species associated with a green alga, Dunaliella tertiolecta, a photoreactor culture of the microalga was investigated using culture-based and culture-independent approaches. The bacterial community structure of the algal culture showed that the most abundant bacterial species under the culture conditions was related to the genus Winogradskyella. The closely related amplicon sequences, showing ≥ 99.5% 16S rRNA gene sequence similarity to one of the isolates, designated IMCC-33238T, constituted > 49% of the bacterial community and was therefore regarded as the most dominant species in the algal culture. Strain IMCC33238T was characterized by Gramstaining-negative and orange-colored rods. Phylogenetic analyses of the 16S rRNA genes as well as whole genome sequences revealed that strain IMCC33238T belonged to Winogradskyella and shared more than 97.2% 16S rRNA gene sequence similarity with Winogradskyella species. The strain contained iso-C15:1 G, iso-C15:0, iso-C15:0 3-OH, and summed feature 3 (C16:1ω6c and/or C16:1ω7c) as major fatty acids and MK-6 as the predominant quinone. The polar lipids found in strain IMCC33238T were phosphatidylethanolamine, two unidentified aminolipids, and three unidentified lipids. The genome of strain IMCC33238T was 3.37 Mbp in size with 33.9 mol% G + C content and proteorhodopsin. Many genes encoding folate and vitamin production are considered to play an important role in the bacteria-algae interaction. On the basis of phylogenetic and phenotypic characteristics, strain IMCC33238T represents a novel species in the genus Winogradskyella, for which the name Winogradskyella algicola sp. nov. is proposed. The type strain is IMCC33238T (= KACC 21192T = NBRC 113704T).


Assuntos
Clorofíceas/microbiologia , Flavobacteriaceae/classificação , Flavobacteriaceae/genética , Flavobacteriaceae/isolamento & purificação , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Benzoquinonas/química , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/fisiologia , Fosfatidiletanolaminas/química , RNA Ribossômico 16S/genética , República da Coreia , Rodopsinas Microbianas/química , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química , Sequenciamento Completo do Genoma
6.
J Microbiol ; 57(11): 991-996, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31659685

RESUMO

A Gram-stain-positive, aerobic, motile, and rod-shaped bacterial strain designated TGS2-1T was isolated from sediment soil in the Nakdong River, Republic of Korea. The optimal growth of strain TGS2-1T was observed at 28°C and pH 7.0 without NaCl supplementation. Strain TGS2-1T revealed antibiosis against various bacteria, including Staphylococcus aureus KCCM 4051, CCARM 3089 (methicillin resistant strains), Enterococcus faecalis KCCM 11814, Escherichia coli KCTC 2443, Candida albicans KACC 7270, and Filobasidium neoformans KCTC 7902. Phylogenetic analyses based on the 16S rRNA gene sequences indicated that strain TGS2-1T belonged to the genus Brevibacillus and shared 93.8-99.7% sequence similarity with Brevibacillus species. Whole-genome sequencing of strain TGS2-1T revealed a genome size of 6.2 Mbp and DNA G + C content of 47.0 mol%. The TGS2-1T genome shared an average nucleotide identity and digital DNA-DNA hybridization of 74.6-93.3% and 18.6-67.1%, respectively, with six related Brevibacillus genomes. The major fatty acid constituents of strain TGS2-1T were anteiso-C15:0 (62.3%) and anteiso-C17:0 (10.8%). Cells of strain TGS2-1T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, seven unidentified aminophospholipids, and five unidentified lipids. The isoprenoid quinone detected in the strain was menaquinone-7 (MK-7). Based on data obtained from this polyphasic taxonomic study, strain TGS2-1T represents a novel species belonging to genus Brevibacillus, for which the name B. antibioticus sp. nov. is proposed. The type strain is TGS2-1T (= KCCM 90326T = NBRC 113840T = FBCC-B2501).


Assuntos
Antibacterianos/biossíntese , Brevibacillus/classificação , Brevibacillus/isolamento & purificação , Brevibacillus/metabolismo , Filogenia , Rios/microbiologia , Microbiologia do Solo , Bactérias/efeitos dos fármacos , Técnicas de Tipagem Bacteriana , Composição de Bases , Benzoquinonas/química , Brevibacillus/genética , DNA Bacteriano/genética , Ácidos Graxos/química , Sedimentos Geológicos/microbiologia , Testes de Sensibilidade Microbiana , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA , Solo , Sequenciamento Completo do Genoma
7.
Chem Biodivers ; 16(12): e1900503, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31660678

RESUMO

A series of 2,5-bis(alkyl/arylamino)-1,4-benzoquinones (1-12) were investigated in vitro for their potential to inhibit the activity of jack bean urease. Compounds 1-6, 8, 9, 11 and 12 effectively inhibited the jack bean urease activity by 90.8 % when tested at 5 µm, whereas 7 and 10 had relatively little effect. The IC50 for most compounds was in the nanomolar range (31.4 nm and 36.0 nm for 2 and 8, respectively). The mechanism of enzyme inhibition shown by 2 and 8 is typical of mixed-type inhibitors, whose affinity for the active site is over 6- and 2-fold higher (Ki =30.0 and 22.8 nm, for 2 and 8, respectively) than that of an allosteric site. Molecular docking studies revealed that both 2 and 8 establish hydrogen bonds with the amino acids residues Asp494, Met588, His593 and Ala636 in the active site of jack bean urease. These results indicate that such aminoquinones are useful leads for the development of more efficient urease inhibitors of wider utility.


Assuntos
Benzoquinonas/química , Inibidores Enzimáticos/química , Urease/antagonistas & inibidores , Sítio Alostérico , Benzoquinonas/metabolismo , Benzoquinonas/farmacologia , Canavalia/enzimologia , Domínio Catalítico , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Cinética , Simulação de Acoplamento Molecular , Relação Estrutura-Atividade , Urease/metabolismo
8.
Chemistry ; 25(67): 15252-15256, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31509280

RESUMO

Metalloenzymes often utilize radicals in order to facilitate chemical reactions. Recently, DeGrado and co-workers have discovered that model proteins can efficiently stabilize semiquinone radical anion produced by oxidation of 3,5-di-tert-butylcatechol (DTBC) in the presence of two zinc ions. Here, we show that the number and the nature of metal ions have relatively minor effect on semiquinone stabilization in model proteins, with a single metal ion being sufficient for radical stabilization. The radical is stabilized by both metal ion, hydrophobic sequestration, and interactions with the hydrophilic residues in the protein interior resulting in a remarkable, nearly 500 mV change in the redox potential of the SQ. - /catechol couple compared to bulk aqueous solution. Moreover, we have created 4G-UFsc, a single metal ion-binding protein with pm affinity for zinc that is higher than any other reported model systems and is on par with many natural zinc-containing proteins. We expect that the robust and easy-to-modify DFsc/UFsc family of proteins will become a versatile tool for mechanistic model studies of metalloenzymes.


Assuntos
Benzoquinonas/química , Metaloproteínas/química , Metais/química , Sequência de Aminoácidos , Sítios de Ligação , Catecóis/química , Interações Hidrofóbicas e Hidrofílicas , Íons/química , Cinética , Ligantes , Modelos Moleculares , Oxirredução , Ligação Proteica , Conformação Proteica , Estabilidade Proteica/efeitos dos fármacos , Termodinâmica
9.
Chemosphere ; 234: 902-908, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31519098

RESUMO

An emerging class of unregulated disinfection byproducts, halobenzoquinones (HBQs), has gained recent interest following suggestions of enhanced toxicity compared to regulated disinfection byproducts. While the kinetics of HBQ hydrolysis in water have been well characterized, the stability of HBQs in cell culture media, a critical parameter when evaluating toxicity in vitro, has been overlooked. The objective of this study was: (1) to contrast the stability of a prevalent HBQ, 2,6-dichloro-1,4-benzoquinone (DCBQ), in cell culture media and water, and (2) to evaluate the cytotoxicity of parent and transformed DCBQ compounds as well as the ability of these compounds to generate intracellular reactive oxygen species (ROS) in normal human colon cells (CCD 841 CoN) and human liver cancer cells (HepG2). The half-life of DCBQ in cell media was found to be less than 40 min, compared to 7.2 h in water at pH 7. DCBQ induced a concentration-dependent decrease in cell viability and increase in ROS production in both cell lines. The parent DCBQ compound was found to induce significantly greater cytotoxicity compared to transformed DCBQ products. We demonstrate that the study design used by most published studies (i.e., extended exposure periods) has led to a potential underestimation of the cytotoxicity of HBQs by evaluating the toxicological profile primarily of transformed HBQs, rather than corresponding parent compounds. Future in vitro toxicological studies should account for HBQ stability in media to evaluate the acute cytotoxicity of parent HBQs.


Assuntos
Benzoquinonas/toxicidade , Desinfetantes/toxicidade , Poluentes Químicos da Água/toxicidade , Benzoquinonas/química , Desinfecção , Água Potável/química , Humanos , Hidrólise , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/análise , Purificação da Água
10.
Mater Sci Eng C Mater Biol Appl ; 104: 109881, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499940

RESUMO

Thymoquinone (TQ) loaded monodispersed mesoporous silica nanoparticles (TQ-MSNPs) with size of 188 ±â€¯3 nm were prepared and characterized using DLS, TEM and FTIR. These TQ-MSNPs overcome the limitations of free TQ like hydrophobicity, low aqueous and photo stability and thus enhance its anticancer activity. In vitro release kinetics showed biphasic drug release where up to 50% was released in first 8 h and subsequently 98% released after 48 h. Enhanced cytotoxicity of TQ-MSNPs was observed against MCF-7 and HeLa cell lines as compared to free TQ. DAPI and Annexin V-FITC/PI staining confirmed the induction of apoptosis in cancer cells following treatment with TQ-MSNPs. Also, TQ-MSNPs exhibited enhanced anti-invasion properties against both cell lines as very low concentration of loaded TQ imparts similar benefits as free TQ. Both TQ and TQ-MSNPs exerted their cytotoxicity via reactive oxygen species (ROS) generation, as addition of an antioxidant NAC attenuated their killing activity.


Assuntos
Apoptose/efeitos dos fármacos , Benzoquinonas/farmacologia , Nanopartículas/química , Invasividade Neoplásica/patologia , Dióxido de Silício/química , Antioxidantes/química , Antioxidantes/farmacologia , Benzoquinonas/química , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Células HeLa , Humanos , Células MCF-7 , Porosidade , Espécies Reativas de Oxigênio/metabolismo
11.
Mol Cell Biochem ; 462(1-2): 195-206, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31493190

RESUMO

Thymoquinone (TQ) is a highly perspective chemotherapeutic agent against gliomas and glioblastomas because of its ability to cross the blood-brain barrier and its selective cytotoxicity for glioblastoma cells compared to primary astrocytes. Here, we tested the hypothesis that TQ-induced mild oxidative stress provokes C6 glioma cell apoptosis through redox-dependent alteration of MAPK proteins. We showed that low concentrations of TQ (20-50 µM) promoted cell-cycle arrest and induced hydrogen peroxide generation as a result of NADH-quinone oxidoreductase 1-catalyzed two-electron reduction of this quinone. Similarly, low concentrations of TQ efficiently conjugated intracellular GSH disturbing redox state of glioma cells and provoking mitochondrial dysfunction. We demonstrated that high concentrations of TQ (70-100 µM) induced reactive oxygen species generation due to its one-electron reduction. TQ provoked apoptosis in C6 glioma cells through mitochondrial potential dissipation and permeability transition pore opening. The identified TQ modes of action on C6 glioma cells open up the possibility of considering it as a promising agent to enhance the sensitivity of cancer cells to standard chemotherapeutic drugs.


Assuntos
Apoptose/efeitos dos fármacos , Benzoquinonas/farmacologia , Glioma/patologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Benzoquinonas/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Glioma/enzimologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Oxirredução , Fosfatidilinositol 3-Quinases/metabolismo , Ratos
12.
Biosens Bioelectron ; 142: 111572, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31400730

RESUMO

We propose herein an immobilization-free, split-mode cathodic photoelectrochemical (PEC) strategy coupled with a cascaded amplification for versatile biosensing. Taking DNA and microRNA (miRNA) as the model targets, the hybridization between the targets and the hairpin probe triggers the digestion of the probe DNA by T7 exonuclease (T7 Exo), thus to generate G-quadruplex (G4) forming sequences, and then the released targets (DNA or miRNA) initiate the subsequent cycling processes and generate a large amount of G4 forming sequences. Subsequently, the formed G4 sequences associate with hemin to form the G4/hemin DNAzyme, which catalytically produces 1,4-bezoquinone (BQ) for conjugating onto the surface of the chitosan (CS) deposited BiOI/ITO photocathode via the quinone-chitosan conjugation chemistry (QCCC). Under photo excitation, the covalently attached quinones can act as electron acceptors of bismuth oxyiodine (BiOI), promoting the photocurrent generation and thus allowing the elegant and "signal-on" mode for probing targets of interest. Highly sensitive and selective PEC bioassays are readily realized, with the detection limits down to 2.2 fM (for DNA) and 0.2 fM (for miRNA). Since no labeling and no electrode modification processes are needed, this split-mode PEC biosensing strategy is amenable to convenient, time/labor saving, and high-throughput detections. More significantly, it provides a novel concept to design immobilization-free and label-free cathodic PEC biosensing systems, and showcases promise in general and versatile bioanalysis research.


Assuntos
Técnicas Biossensoriais/instrumentação , DNA/análise , MicroRNAs/análise , Hibridização de Ácido Nucleico , Benzoquinonas/química , Sondas de DNA/química , DNA Catalítico/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Desenho de Equipamento , Quadruplex G , Hemina/química
13.
J Microbiol ; 57(11): 967-975, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31463791

RESUMO

A polyphasic taxonomy approach was used to characterize strain YBJ-36T, isolated from a freshwater lake in Taiwan. Phylogenetic analyses, based on 16S rRNA gene sequences and coding sequences of an up-to-date bacterial core gene set (92 protein clusters), indicated that strain YBJ-36T formed a phylogenetic lineage in the genus Mucilaginibacter. 16S rRNA gene sequence similarity indicated that strain YBJ-36T is closely related to species within the genus Mucilaginibacter (93.8-97.8% sequence similarity) and is most similar to Mucilaginibacter fluminis TTM-2T (97.8%), followed by Mucilaginibacter roseus TTM-1T (97.2%). Microbiological analyses demonstrated that strain YBJ-36T is Gram-negative, aerobic, non-motile, rod-shaped, surrounded by a thick capsule, and forms pink-colored colonies. Strain YBJ-36T grew between 20-40°C (optimal range, 35-37°C), pH 5.5-7.0 (optimal pH of 6) and 0-2% NaCl (optimal concentration, 0.5%). The predominant fatty acids of strain YBJ-36T are iso-C15:0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c), the major polar lipid is phosphatidylethanolamine, the major polyamine is homospermidine, and the major isoprenoid quinone is MK-7. The draft genome is approximately 4.63 Mb in size with a G+C content of 42.8 mol%. Strain YBJ-36T exhibited less than 35% DNA-DNA relatedness with Mucilaginibacter fluminis TTM-2T and Mucilaginibacter roseus TTM-1T. Based on phenotypic and genotypic properties and phylogenetic inference, strain YBJ-36T should be classified in a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter limnophilus sp. nov. is proposed. The type strain is YBJ-36T (= BCRC 81056T = KCTC 52811T = LMG 30058T).


Assuntos
Bacteroidetes/classificação , Bacteroidetes/isolamento & purificação , Lagos/microbiologia , Filogenia , Microbiologia da Água , Técnicas de Tipagem Bacteriana , Bacteroidetes/genética , Bacteroidetes/fisiologia , Composição de Bases , Benzoquinonas/química , DNA Bacteriano/genética , Ácidos Graxos/química , Lipídeos/química , Hibridização de Ácido Nucleico , Fosfatidiletanolaminas/química , Poliaminas/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Taiwan , Sequenciamento Completo do Genoma
14.
Chem Commun (Camb) ; 55(65): 9681-9684, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31347618

RESUMO

Here, we report a convenient, fast labeling strategy for the imaging of cell surface sialic acids (SAs, nine-carbon monosaccharides located at the terminals of cell surface sugar chains). This strategy is based on the synthesis of sticky, furry and fluorescent "wool-balls", which are wound into nanoclusters from p-benzoquinone/ethylenediamine polymer "wires". With abundant amino groups at the surface, the wool-balls can easily stick to the C-7 aldehyde group generated at the ends of periodate treated SAs in less than 30 min.


Assuntos
Benzoquinonas/química , Etilenodiaminas/química , Corantes Fluorescentes/química , Nanopartículas/química , Polímeros/química , Ácidos Siálicos/análise , Animais , Benzoquinonas/síntese química , Linhagem Celular Tumoral , Etilenodiaminas/síntese química , Fluorescência , Humanos , Camundongos , Microscopia de Fluorescência/métodos , Neuraminidase/química , Tamanho da Partícula , Polímeros/síntese química , Células RAW 264.7 , Bases de Schiff/síntese química , Bases de Schiff/química , Ácidos Siálicos/química
15.
Molecules ; 24(13)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277409

RESUMO

We report the development of a new colorimetric probe (L-ol) for investigations of the redox process regulated by hypochlorous acid (HOCl) and glutathione (GSH). The HOCl/GSH redox-switching cycle process was investigated in detail by UV-vis absorption spectroscopy, colorimetric analysis assay and high-resolution mass spectrometry (HRMS). The switchable absorbance responses were attributed to the HOCl-induced oxidation of the p-methoxyphenol unit to the benzoquinone derivative (L-one) and sequential reduction of L-one to hydroquinone (L-ol') by GSH. In phosphate-buffered saline (PBS) buffer, the absorbance of L-ol at 619 nm underwent a remarkable bathochromic-shift, accompanied by a color change from pale yellow to blue in the presence of HOCl. With further addition of GSH, the absorbance of L-one exclusively recovered to the original level. Meanwhile, the blue-colored solution returned to the naive pale yellow color in the presence of GSH. The detection limits for HOCl and GSH were calculated to be 6.3 and 96 nM according to the IUPAC criteria. Furthermore, L-ol-loaded chromatography plates have been prepared and successfully applied to visualize and quantitatively analyze HOCl in several natural waters.


Assuntos
Colorimetria/métodos , Glutationa/análise , Ácido Hipocloroso/análise , Benzoquinonas/química , Cor , Hidroquinonas/química , Sondas Moleculares/síntese química , Sondas Moleculares/química , Oxirredução , Espectrofotometria Ultravioleta , Fatores de Tempo , Água/química
16.
Mater Sci Eng C Mater Biol Appl ; 102: 773-787, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147050

RESUMO

Oxidative stress is critically attributed for impeding tissue repair and regeneration process. Elimination of over-accumulated, deleterious reactive oxygen species (ROS) could be elicited to accelerate healing in tissue engineering applications. Antioxidant biomolecules play a pivotal role in attenuating oxidative stress by neutralizing the free radical effects. Herein, we describe the synthesis and fabrication of novel quinone-based chromenopyrazole (QCP) antioxidant-laden silk fibroin (SF) electrospun nanofiber scaffold (QCP-SF) for tissue engineering applications. The spectral characterization of the synthesized compounds (6a-6h) were analysed by using NMR, FTIR and mass spectra and cell viability study of all the synthesized compounds were evaluated by MTT assay in primary rat bone marrow stem cells (rBMSCs). Among the prepared molecules, compound 6h showed an excellent cell viability, and antioxidant efficacy of compound 6h (QCP) was investigated through 1,1­diphenyl­2­picrylhydiazyl (DPPH) scavenging assay. QCP expressed high antioxidant activity with IC50% of DPPH scavenging was observed about 5.506 ±â€¯0.2786 µg. Novel QCP laden SF fiber scaffolds (QCP-SF) were characterized and incorporation of QCP did not affect the nanofiber architecture of QCP-SF scaffold. QCP-SF scaffold exhibited an enhanced thermal and mechanical stability when compared to native SF fiber mat. In vitro biocompatibility studies were evaluated using NIH 3T3 fibroblasts and rBMSCs. The QCP-SF scaffold displayed an increased cell attachment and proliferation in both cell types. In vitro wound healing study (scratch assay) of QCP-SF scaffold showed an excellent cell migration with NIH 3T3 cells into scratch area and complete cell migration occurred within 24 h. Based on results, we propose that QCP-loaded SF (QCP-SF) nanofibrous scaffolds can serve as a promising potential antioxidant fibrous scaffold for skin tissue engineering applications.


Assuntos
Antioxidantes/farmacologia , Benzoquinonas/síntese química , Fibroínas/química , Nanofibras/química , Pirazóis/síntese química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Benzoquinonas/química , Materiais Biocompatíveis/farmacologia , Bombyx , Adesão Celular/efeitos dos fármacos , Morte Celular , Proliferação de Células/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Células NIH 3T3 , Nanofibras/ultraestrutura , Pirazóis/química , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Resistência à Tração , Água/química , Cicatrização/efeitos dos fármacos
17.
Food Chem ; 297: 124932, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253253

RESUMO

A red colored caffeic acid trimer was synthesized in model solution by enzymatic oxidation. The structure was elucidated by mass spectrometry and NMR spectroscopy and consisted of four carbon rings and two unsaturated acyl side chains. A formation pathway is suggested which includes the formation of a caffeic acid ortho-quinone followed by a Michael-type reaction, and radical coupling of a semiquinone of the formed dimer and a third caffeic acid molecule. The final structure is formed by decarboxylation and cyclisation. Results of ESI-MSn analysis can be explained by the presence of two carboxylic acid groups and a tetracyclic structure. The relative configuration of the central chiral carbons was deduced by NOESY experiments.


Assuntos
Ácidos Cafeicos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Benzoquinonas/química , Ácidos Cafeicos/isolamento & purificação , Ácidos Cafeicos/metabolismo , Cromatografia Líquida de Alta Pressão , Distribuição Contracorrente , Monofenol Mono-Oxigenase/metabolismo , Oxirredução , Polímeros/química
18.
Chemosphere ; 232: 273-280, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31154188

RESUMO

Biochar has been proven to possess the electron transfer property that can participate in the biogeochemical redox reaction in the environment. In this study, the electron accepting capacities (EACs) of the barley grass biochars produced at the various temperatures from 350 °C to 800 °C were investigated. The EAC values were in the range of 0.27-0.72 mmol e- (g biochar)-1 and showed increase as the pyrolysis temperature increased from 350 °C to 450 °C, slight decrease with temperature increasing from 450 °C to 500 °C, and then increase again from 650 °C to 800 °C. The O-containing groups were the EAC moieties identified by temperature programmed desorption coupled with mass spectroscopy (TPD-MS) and fourier transform infrared spectroscopy (FTIR) and carbonyl and quinone were the main EAC moieties, accounting for 75.4%-95.7% as the pyrolysis temperature increased from 350 °C to 800 °C. Overall, carbonyl and quinone determined the EACs properties of biochar which were affected by the pyrolysis temperature. The results will help us to develop biochar with controlled electron accepting property for specific environmental applications.


Assuntos
Pirólise , Quinonas/química , Benzoquinonas/química , Carvão Vegetal/química , Elétrons , Hordeum , Temperatura Alta , Oxirredução , Quinonas/agonistas , Quinonas/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente
19.
Environ Res ; 175: 343-350, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31150933

RESUMO

In this work, we investigate the photolysis behavior of 2,3-dibromo-5,6-dimethyl-1,4-benzoquinone (DDBQ), the only dibrominated benzoquinone detected in treated water so far. DDBQ solutions prepared in ultra-pure water were exposed to UV radiation centered at 254 nm (UV254), and the photolysis of the parent compound was monitored together with by-product formation. The DDBQ pseudo-first order photolysis rate constants decreased when increasing the initial DDBQ concentration, and this behavior was caused by saturation of absorption. The photodegradation kinetics was found not to depend on pH and 1-butanol addition, but was affected by humic acids and components that occur in both natural waters and treated wastewater. For the first time with this class of compounds, photolysis studies were also performed using natural and treated wastewater matrices, where photodegradation was always found to proceed significantly slower than in ultra-pure water. The implications for the radiation dose that is required to reach a given treatment target are discussed, and a numerical approach by which to foresee the extent of degradation inhibition is provided that should be taken into account when planning the UV254 treatment of DDBQ. The phototransformation of DDBQ yielded hydroxyderivatives, most likely via a debromination-hydroxylation pathway. In-silico toxicity screening suggested that the transformation of DDBQ into the detected hydroxyderivatives would not eliminate toxicity. Although the monohydroxylated derivative underwent relatively fast transformation, the dihydroxylated compound was found to accumulate during irradiation. As a compromise, the irradiation conditions that produce over 90% degradation of DDBQ in the studied samples, and at the same time keep by-product formation low are discussed.


Assuntos
Benzoquinonas/química , Poluentes Químicos da Água/química , Benzoquinonas/análise , Cinética , Processos Fotoquímicos , Fotólise , Raios Ultravioleta , Águas Residuárias/química , Água , Poluentes Químicos da Água/análise
20.
Talanta ; 202: 384-391, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171199

RESUMO

A novel microfluidic paper-based analytical device (µPAD) was developed with benzoquinone (BQ)-mediated E. coli respiration method to measure the biotoxicities of pollutants. Functional units including sample injection, fluid-cell separation, all-carbon electrode-enabled electrochemical detection, were integrated on a piece of chromatography paper. The three-electrode, working electrode, counter electrode and reference electrode, were simultaneously screen-printed on the µPAD with conductive carbon ink. The satisfying electrochemical performance of the paper-based carbon three-electrode was confirmed by cyclic voltammetry detecting K3 [Fe(CN)6]. The process of cell toxication was considered that toxicants inhibited cell respiration and diminished the electrons on E. coli respiratory chain. It was quantitatively reflected by measuring oxidation current of hydroquinone (HQ) as a reduced state of the redox mediator BQ after the incubation of cells with pollutants. The current detection time, BQ concentration and E. coli incubation time were carefully optimized to establish the systematic optimized operations of BQ-mediated E. coli respiration method. Using the fabricated µPAD the half inhibitory concentration (IC50) were Cu2+ solution 13.5 µg mL-1, Cu2+-soil 21.4 mg kg-1, penicillin sodium-soil 85.1 mg kg-1, and IC30 of Pb2+ solution was 60.0 µg mL-1. Detection of pesticide residues in vegetable juices were accomplished in a similar way. The proposed method is fascinating on three points; 1) The generality in the biotoxicity detection depends on toxicants inducing cellular respiratory inhibition; 2) The portability and affordability make it convenient for practical applications, because of replacing incubators and centrifuges; 3) There is potential applicability in less-developed areas due to its simple operation and low-cost.


Assuntos
Técnicas Eletroquímicas , Poluentes Ambientais/farmacologia , Escherichia coli/efeitos dos fármacos , Técnicas Analíticas Microfluídicas , Papel , Benzoquinonas/química , Eletrodos , Poluentes Ambientais/análise , Escherichia coli/citologia , Escherichia coli/metabolismo
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